Abstract: Despite the actual two-year closure of schools, the use of Modular Distance Learning (MDL) is crucial to the ongoing education of students. As a result of its adoption, the global educational landscape was completely transformed, and difficulties were inevitable for this new kind of instruction (Castroverde, 2021). This study sought to investigate the challenges encountered by teachers in the implementation of modular distance learning modality in one the districts of a big-sized division in Central Philippines for the School Year 2020-2021. This descriptive-quantitative study was conducted in seven (7) components schools with 131 respondents taken from the total population of 198 teacher. The independent variables were age, civil status, highest educational attainment and length of service. A self-made questionnaire was used in this study, and it passed the validity and reliability test. The areas used for the determination of challenges were content preparation, distribution and retrieval and feedback giving and assessment. The result of the study showed that the degree of challenges of teachers in Content Preparation is moderate (M=2.50, SD=0.2574). The degree of challenges in Distribution and Retrieval (M=2.37; SD=0.721), and Feedback Giving/Assessment were on low level (M=2.18; SD=0.5144). Furthermore, there was a significant difference in the degree of challenges encountered by teachers in the implementation of modular distance learning when grouped and compared according to aforementioned variables. The study recommended the creation of a working group who will take charge of downloading instructional materails, per grade level, which later will be distributed to teachers,to reduce the traffice from DepEd website; and the utilization of a single room for the synchronized disinfection treatment of returned modules. Keywords: Challenges encountered, Modular distance learning modality.